U-tube manometer with shipping seal



Nov. 24, 1970 J. E. BoNczEK U-TUBE MANOMETER WITH SHIPPING SEAL FiledJuly 25, 1968 United States Patent O 3,541,858 U-TUBE MANOMETER WITHSHIPPING SEAL Joseph E. Bonczek, Elyria, Ohio, assignor, by ruesneassignments, to The Scott & Fetzer Company, Lakewood, Ohio, acorporation of Ohio Filed July 25, 1968, Ser. No. 747,896 Int. Cl. G01l7/18 U.S. Cl. 73-401 7 Claims ABSTRACT OF THE DISCLOSURE `Combinationincluding a removable internal seal for a bore, especially adapted forsealing liquid inside tubing, such as sealing mercury inside aclosed-end, absolute pressure gauge, U-tube, wherein the seal is adaptedto be inserted into a long bore, to be moved into sealing position orinto a removable position by manipulation from outside of the bore, andto follow the expansion or contraction of the liquid in the bore withoutpermitting air leakage between the seal and the liquid surface.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to aremovable, internal seal for a bore and any suitable combinationcontaining that seal. More specifically, the invention relates tosealing a bore in tubing with said seal, and still more specificallyrelates to sealing mercury in a mercury lled, closed-end, absolutepressure U-tube for a manometer, as disclosed herein.

The closed-end, glass, absolute pressure U-tube of a manometer has theleg of its closed end iilled full, and of its open end filled only to ashort distance around the U-bend, as shown in FIG. 3, when its is firstfilled. After filling and during shipping, the problem is to hold themercury in the U-tube, in the same manner as it is iilled by themanufacturer; so that in shipment to the user of the U-tube, the mercuryis not lost nor is air permitted to get into the mercury where it mightmigrate through the mercury, around the U-bend and into the closed endof the U-tubev to break the vacuum therein, or to reduce the completefilling of the closed end with mercury.

The seal of the present invention solves all of these problems by beingeasily insertable into the open end after the U-tube has been filledwith mercury, sealing the surface of the mercury against air entrythereto, readily following the surface of the mercury during itsexpansionv or contraction to prevent breakage of the glass tube byexpansion of the mercury and to prevent entry of air thereto duringcontraction, and readily removable from the open end of the U-tube whenthe U-tube reaches its destination and is ready for use.

This seal may be used either in a shipping block for shippingreplacement U-tubes lled with mercury or in the original manometer capblock used not only to cap the orignnal U-tube during shipment of theoriginal manometer but also as a cap block in the manometer duringmanometer operation.

An object of the present invention is to provide a seal for a boreeasily movable by manipulation from outside the bore into a sealingposition for sealing the bore or into a removable position for removalfrom the bore and/or for following the surface of any liquid within thebore during any expansion or contraction of the liquid therein.

A further object of the present invention is to provide a seal forretaining mercury within a U-tube of a manometer whether the U-tube hasone open and one closed end or both open ends.

3,541,858 Patented Nov. 24, 1970 ICC A further object of the presentinvention is to provide a block clampable over the distal ends of amanometer U-tube for resiliently and detachably retaining a seal formercury therein and/ or supporting and spacing apart the distal ends ofthe U-tube while any deflecting force is applied thereto, such as duringshipping or use.

A further object of the present invention is to provide a seal for abore having two axially spaced apart and radially expandable andcontractible O-rings for providing a leak-proof seal easily slidable byan axial force within the bore and easily removable from the bore, whendesired.

A further object of the present invention is to provide a seal with orwithout a retaining block and adapted to be used with a U-tube of amanometer characterized by its inexpensive manufacturing cost, ease ofassembly of its component parts, structural simplicity, many desirableoperational advantages, ease of operation oruse, and multiplicty offunctional advantages for some component parts thereof.

These and other objects, novel features and additional advantages of thepresent invention will become more clearly apparent by reference to theappended claims as the following detailed description and discussionproceeds in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing,

FIG. 1 is an elevational view, partially in section, of a flow conduitand a manometer using a mercury filled, closed-end, absolute pressureU-tube for measuring the upstream pressure in the flow conduit forgiving the characteristics of flow through the ilow orifice thereof toatmosphere by measuring absolute pressure;

FIG. 2 is a perspective view of a shipping unit for ship- Vping areplacement U-tube for the manometer in FIG l;

FIG. 3 is a longitudinal sectional view of the shipping unit in FIG. 2;and

FIG. 4 is an enlarged, side elevational view, partially in section, ofthe seal in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the presentinvention in a seal has many uses, it will be specifically disclosedherein in connection with U-tube 20 of absolute pressure manometer orgauge 18 in FIG. 1.

Manometer or gauge 1'8 may be of any suitable type with its usual usagebeing disclosed in FIG. 1. There, fluid is flowing in flow direction Dthrough flow conduit 10 and through orilice 12 to atmosphere, andmanometer or gauge 18 is used to aid in obtaining the characteristics(volume, velocity, etc.) of the owing fluid by giving the pressure dropmeasured across orice 12 by the upstream pressure being transmittedthrough upstream pressure tap 14 in conduit 10, and flexible pressureline 16 to open end 20a of U-tube 20 in manometer or gauge 18. Since theother end of U-tube 20 is closed end 20b, absolute pressure P in FIG. lis measured by manometer or gauge 18 to be used in calculating any ofthese characteristics.

Manometer or gauge 18 includes a plurality of interconnected parts,including U-tube 20, mercury 22, base 24, clamps 26, scale 28, screws30, manometer cap block 32, and gaskeets 25.

U-tube 20 has at least one open end 20a with a generally uniformdiameter bore 20c, similar to a bore of tubing, therein containingmercury. Although it should be readily apparent hereinafter that someaspects of this invention may be used with a manometer U-tube havingboth ends open connected by a uniform diameter bore, it has been chosento show herein U-tube 20 having one 3 closed end 20h to form an absolutepressure gauge. This closed end is now completely lled with mercury, atthe time of lling, so as to evacuate all air therebetween to keep thespace between the surface of the mercury (in the space between the openend U-leg and closed end 2Gb) free of air and to keep closed end 20bsubstantially a vacuum. Flow restriction 20d is located in bore 20c toserve as a surge damper. For example, if a high vacuum is being sensedby pressure line 16 and this vacuum is suddenly vented to atmosphere,this surge damper or throttling means 20d restricts the speed of mercurytravel toward closed end 20b to prevent the possibility of the mercuryknocking off closed end 2Gb by its rapid Velocity.

Although any suitable liquid may be contained in tube 20, it isgenerally lled with mercury.

Gauge base 24 is here shown as a one-piece casting comprising sheet-likebase plate 24b, coplanar with the plane of the drawing; U-shaped wall24d and cap 24f extending around the periphery of base plate 2417 andout of the plane of plate 24b in the direction out of the plane of thedrawing; and recess 24h, formed by wall 24d and cap 24]c and greater indepth than the thickness of U-tube 20, seen in front of base plate 24hin FIG. 1. U-tube 20 is mounted in recess 24h by telescoping its twodistal ends 20a and 2Gb through two annular gaskets 25 telescoped intoparallel holes 24m in cap 24h; swinging the base of the U toward plate24h and into recess 24h; and detachably securing U-tube 20 in recess 24hby one or more detachable clamps 26.

Manometer scale 28, having graduations 28a thereon for measuringabsolute pressure by measuring the differential heights of the mercurycolumns in the two legs of the U-tube 20, is secured by one or morescrews 30 with each screw 30 extending through slot 28b in scale 28 andscrewed into a threaded hole carried by base plate 24b.

Suitable clamping means 33 secures block 32 to base 24. Manometer capblock 32 is secured to base 24 by stud 34, rigidly secured at its lowerend to base 24, such as in a threaded hole in cap 24f, extending upthrough a central hole in block 32, and having a wing nut 36 screwedonto threaded upper end of stud 34. When nut 36 is tightened, it pullsblock 32 downwardly in FIG. 1 to Squeeze gaskets 25 to mount resilientlyand firmly the upper and distal ends 20a and 20b of U-tube 20 in base 24to form complete manometer or gauge 18.

Block 32 may be made of any suitable material but is generally made ofmetal, has two axially extending parallel holes 32a and 32b forreceiving respectively U-tube ends 20a and Z012, and has pressure port32]c extending laterally from hole 32a and adapted to be detachablyconnected at its outer end with pressure line 16.

U-tube 20, when removed from gauge 18, is filled with mercury 22 alongthe full length of its leg having closed end 2Gb, around the base of theU, and along a short distance up the other leg toward open end 20a. Theproblem is to hold the mercury in the open end leg of the U-tube so thatin shipment the mercury is not lost (runs out of) U-tube 20, nor is airpermitted to get into the mercury where it might migrate around theU-bend to get into the mercury in the leg having the closed end so as tobreak the Vacuum or to reduce the complete lling of the closed end leg.

Removable, internal, piston-type seal 40 in FIGS. '2, 3 and 4 is used toseal or hold the mercury in U-tube bore 20 in the desired manner. Seal40 includes rod 42, sealing means 44 and suitable seal control means 48.

Rod 42 is shown herein as a smooth, metal rod, having enlarged head 42aand threads 42h at opposite ends connected by smooth cylindrical portion42e of uniform diameter; and adapted to telescope into bore 20c, asshown in FIG. 3, where this seal is in its sealing position.

Sealing means 44 includes one or more seal members 45 and one or morecollars 46 and 47, each shown herein as annular in shape, telescopcdonto, surrounding, op-

eratively connected to cylindrical portion 42e of rod 42 and beingtelescopable with rod 42 into bore 20c into sealing position shown inFIG. 3. Here, seal members 45 comprise two, axially aligned, annular,resilient, O- ring seal members 45 made of suitable rubber-like materialsnugly surrounding and telescoped over rod cylindrical portion 32C.These two seal members 45 are preferably of equal size, as shown in thedrawing, for forming two, parallel, axially spaced apart, circular sealshaving the same durometer hardness and forming seals with uniformdiameter, cylindrical bore 20c. However, it should be readily apparentthat these seal members 45 may have different durometer hardnesses, suchas a softer durometer in the lowermost sealing member in FIGS. 3 and 4to provide a better sealing action and a harder durometer inthelowermost sealing member in FIGS. viding a better centering alignment inbore 20c. Also, one of the seal members 45 may have a larger peripheraldiameter relative to the axis of rod 42 or may have a larger circularcross sectional diamter of its annulus (shown by the rubber crosshatching in FIG. 4) than the other seal member 45 to give certainpreferred characteristics to seal 40.

Seal control means 48 is provided with rod 42 for moving sealing means44 into sealing position for sealing bore 20c or into a removableposition for removal from bore 20c. Although this seal control means 48may take the form of a manually graspable portion on the upper end ofrod 42 in FIGS. 3 and 4 so that sealing means 44 could be pushed as axed piston downwardly into the sealing position shown in FIG. 3 orpulled axially in the upward direction until sealing means 44 clear theupper end of open end 20a in the removable position, seal control means48 is shown herein as having a seal adjusting means 49 operativelyconnecting rod 42 and sealing means 44 and having manually adjustableportion 5l adjustable from outside bore 20c in FIG. 3 for moving, by arelative rotational movement, sealing means 44 between these positionwhile sealing means 44 is in bore 26C. Seal control means 48 includessleeve means 52 (comprising washer `54, sleeve 55 and one or morecollars 46, 47 coacting with rod head 42a and seal members 45)telescoped over rod 42 and operatively connected to sealing .means 44;and manually adjustable portion 51, here shown as nut 5l screwed ontorod threads 42b. Then, rotation of nut 51 advancing in the axialdownward direction in FIG. 3 causes relative axial movement of rod 42and the annular portions of sleeve means 52 for axially squeezing sealmembers 45 so as to radially expand seal members 45 from theircontracted or removable position into their expanded or sealing positionfor sealing against bore 20c.

It should be readily apparent that seal 40 may be used to seal by itssealing means 44 the bore in any tubing or in specic U-tube 20 withoutthe use of block 32 in FIG. l or block 132 in FIGS. 2 and 3. Seal 40 canbe telescoped downwardly in FIG. 3 into open end 20a and bore 20c toseal this bore with seal 40 in the sealing position shown in FIG. 3.Since sleeve means 52 and rod 42 provide an axially elongated dimensionbetween sealing means 44 and manually adjustable nut 51, manualadjustment can be made at nut 51, located outside bore 20c and open end20a and far removed from sealing means 44, for sealing bore 26e bysealing means 44 far within tube bore 20c. As nut 51 is rotated in itsdownwardly advancing direction to expand seal members 45 radiallyoutwardly into their sealing position into sealing engagement with bore20c, two equal sized O-ring seal members 45 form two parallel, coaxialand circular seals with bore 20c. This action also squeezes the bore ifO-ring seal members 45 radially inwardly into resilient engagement withthe periphery of cylindrical portion 42e of rod 42 in sealing engagementin the sealing position for preventing, by this sealing action with bore20c and rod portion 42e, liquid mercury in bore 20c from travelingupwardly past sealing means 44 in FIG. 3. This same action also causeslower O-ring seal member 45 to be squeezed axially against thetransverse planar face of lower collar 46 in FIG. 3 to form a circularseal therewith by resilient engagement; if this lower collar either wereformed as an enlarged, integral head on the lower end of rod y42, or hada tight fitting hole telescoped over the periphery of rod portion 42e,this sealing engagement with the collar and of the periphery of O-rings45 lwith bore 20c would prevent liquid mercury 22 in bore 20c fromtraveling upwardly past sealing means 44.

Seal -40 retains mercury 22 within tube 20, prevents air from enteringto break the vacuum during shipment of tube 20 and permits easywithdrawal of seal 40 from bore 20c when tube 20 has reached itsdestination of ultimate use. First, seal 40 can be moved into sealingposition by axially inserting sealing means 44 downwardly into theposition shown in FIG. 3, and then rotating nut 51 in the downwardlyaxially advancing direction expands O-rings 45 into sealing positionwith bore 20c. Second, sealing means 44 follows the surface of mercury22, as it expands and contracts, by moving axially in bore 20c in theappropriate direction as mercury filled U-tube 20 is handled, such asduring shipping or transit. As variations in temperature occur, mercury22 is caused to expand `or contract. Expanding mercury will push sealingmeans 44 in the upward axial direction in FIG. 3, while atmosphericpressure will push sealing means 44 in the downward direction to followthe surface of mercury 22 without the introduction of air bubblesaxially downwardly past sealing means 44 into mercury 22.. Also, as themercury contracts, vacuum is formed on the mercury surface side ofsealing means 44 to aid this axial downward movement of sealing means44. Hence, sealing means 44 freely axially follows the surface ofmercury liquid 22 in the sealing position on axial expansion orcontraction `of mercury 22 in tube 20. Third, when the shippingdestination is reached and after the U-tube is ready for use to measureflow pressures, seal `40 is readily removable from bore 20c by rotationof nut 51 in the opposite direction to permit contraction of the outerperipheral sealing surface of O-rings 45 by their resiliency to permitaxial upward removal of seal 40 from bore 20c.

The illustrated construction has been found superior to other triedconstructions for many reasons. Some types sealing means 44 will stickin sealing position to bore 20c to prevent ready removal when use isdesired, some have oil or other volatiles therein that will bleed outduring rough handling in transit or during long storage to cause them tostick to bore 20c, some have to be squeezed so tightly in order toprovide a good sealing action that they stick to the glass. In anyevent, any sticking, vulcanizing or practically cementing of sealingmeans 44 onto the surface of bore 20c will prevent sealing means 44 fromfollowing the surface of the mercury during expansion and contraction ofthe long mercury column 22, extending between closed end 20b and sealingmeans 44, upon variations in temperature; and will prevent subsequentre-moval of seal members 45 from bore 20c. Two, parallel, -O-ring, sealmembers 45 have the advantage over a single, O-ring, seal member inproviding a double seal, minimizing the danger of cocking seal 40 inbore 20c, and minimizing the danger of leakage axially therepast since anick or groove in the periphery of one O-ring, seal member 45 mightpermit some leakage therepast but the second O-ring -will prevent anysubstantial portion of this leakage from moving axially past it.

The axial length of seal 40 can be of any desired length governed by theaxial distance between the manually adjustable portion 51 and sealingmeans 44 thereon. Seals 40 of six to thirty inch axial length have beenused satisfactorily.

Although liquid mercury 22 is specically shown herein, it should bereadily apparent that sealing means 44 and seal 40 can be used to holdany liquid or fluid in any suitable recess or container having a bore,such as tubing, even though closed end U-tube 20 is specifically shownherein.

The article or U-tube having a bore to be sealed can be made of anysuitable material even though U-tube 20 is shown herein as being made ofglass. For example, stainless steel U-tubes 20 for manometers or gauges18 are frequently used and can be sealed with seal 40; these stainlesssteel tubes generally use a magnetic follower for detecting the surfaceof the mercury for measuring the absolute pressure P in FIG. 1 sincethis surface is not visible through the side of the tube.

Also, even though U-tube 20 is shown as having one closed end 20b, itshould be readily understood that two seals 40 can be used, one in eachopen end, to seal both open ends of an open ended IU-tube commonly foundin manometers so as to seal the mercury therein during shipment.

Seal `40 is also usable with retaining block 32 or 132, if so desired,to form a shipping unit. Seal 40 can be used with either metal manometercap block 32 in manometer or gauge 18 as originally shipped by themanufacturer to the user in the assembled condition shown in FIG. l butwith seal 40 sealing mercury 22 therein, or Vwith wood shipping block132 in FIGS. 2 and 3 when shipping a replacement U-tube 20 filled withmercury 22 at a later date to a user of manometer 18. Blocks 32 and 132respectively have two parallel holes 32a, 321) and 132a, 132b thereintelescoped over the distal ends 20a and 20b of U-tube 20 to cover thesealed open end 20a and to support these disal ends against anydistortion, such as lateral distortion tending to break glass U- tube20; port or vent means 32f and 1323 extending generally radially fromholes 32a and 132:1 in fluid communication with open end 20a of tube 20for permitting air pressure to be exerted on the outer face of sealingmeans 44 in seal `4() to force sealing means 44 axially downwardly inFIG. 3 against the liquid mercury surface by air pressure to compensatefor any expansion or contraction of the liquid mercury column; clampingmeans 33 and 133 for detachably clamping blocks 32 and 132 to U-tubedistal ends 20a and 20b; and spring 61 and washer 63 telescoped over theupper, distal threaded end 42h of rod 42.

U-tube 20 is shown in its operative position for use in manometer 18 inFIG. l with its pressure port 321 extending generally radially from hole32a in fluid communication with open end 20a and having outwardlyextending tube-like portion for telescopically receiving pressure line16 during manometer use without using seal 40, spring 61 and washer 63under cap block 32. It should be readily apparent that seal 40, spring61 and washer 63 might be assembled in aligned holes 20a, 32a in themanometer assembled position in FIG. 1 in the same manner as shown inFIG. 3 when the manometer is originally shipped to its user so that seal40 could provide the same mercury sealing function. Since thisconstruction is readily apparent, it has not been shown in FIG. 1wherein manometer 18 is shown in its actual operating and pressuremeasuring position.

Clamping means 133 in FIGS. 2 and 3 includes slit 132s in wood block 132extending diametrically of hole 132:1 therein supporting open end 20a,and bolt or screw 134, extending generally tangentially of tube 20 atupper end 20a and through the parallel arms of block 132 straddling slit132s, to permit pulling the two arms together during tightening of screw134 to clamp them firmly on the distal end of U-tube 20 at closed end20a to secure block 132 to end 20a of U-tube 20.

Clamping means 33 or 133 holds respectively block 32 or 132 onto tube 20to prevent axial relative movement between the block and open end 20a sothat helical spring `61 will force washer 63 axially downwardly againstthe top of nut S1 to urge resiliently seal 40 in FIG. 3

axially downwardly with sealing means 44 being urged against the surfaceof liquid mercury 22. Hence, spring 61 serves as a resilient meansoperatively connected to seal 40 and through block 32 or 132 to tube 20for urging sealing means 44 of seal 40 against liquid mercury 22 sealedin tube 20 by sealing means 44 so that this piston-type sealing means 44will follow the surface of the mercury during any expansion orcontraction thereof to prevent any air leaking past the sealing meanstoward the mercury tending to break the vacuum therebetween or into themercury toward sealed and closed tube end 2Gb. It should be readilyapparent that good sealing and mercury liquid surface following actionby sealing means 44 may be obtainable without using spring 61 or withoutusing block 32 or 132 but by using only seal 40, but the sealing andfollowing action may be improved by the use of spring 61 and block 32 or132.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therfore to be considered in all respects asillustrative and not restrictive.

What is claimed and desired to be secured by U.S. Letters Patent is:

1. In combination,

a U-tube with at least one open end with a bore therein;

a removable, internal, piston-type seal telescoped into said Open endand bore to seal said bore, comprising a rod adapted to telescope intosaid bore,

sealing means on said rod telescopable with said rod into said bore, and

seal control means on said rod for moving said sealing means intosealing position for sealing said bore or into a removable position forremoval from said bore;

a block having two parallel holes telescoped over the distal ends of theU-tube to cover said sealed open end and to support said distal endsagainst distortion;

resilient means operatively connected to said block and seal for urgingthe sealing means of said seal against liquid sealed in said tube bysaid sealing means; and

means for holding said block on the U-tube.

2. The combination, as set forth in claim 1, with said holding meanscomprising clamping means on said block for detachably clamping saidblock to said distal ends.

3. The combination, as set forth in claim 1, with said U-tube being amanometer tube,

said U-tube containing liquid mercury therein as a liquid sealed in saidtube by said sealing means.

4. The combination, as set forth in claim 1, with said sealing meanssurrounding said rod and being operatively connected to said rod,

said seal control means including seal adjusting means operativelyconnecting said rod and sealing means and having a manually adjustableportion adjustable from outside said bore for moving said sealing meansbetween said positions while said sealing means is in said bore,

said seal control means including a sleeve means telescoped over saidrod and operatively connected to said sealing means and said manuallyadjustable portion.

5. The combination, as set forth in claim 2, with said block being ashipping block for said manometer,

said clamping means including said block being slit diametrically of thehole therein supporting said open end and having a screw extendinggenerally tangential to the tube at said open end and through said slit.

6. The combination, as set forth in claim 1, with said block including aport extending generally radially from its hole in uid communicationwith said open end and having means for receiving a pressure line duringmanometer use when said sealing means and resilient means 30 have beenremoved.

7. The combination, as set forth in claim 1, with said sealing meanscomprising two axially aligned annular resilient rubber O-ringstelescoped over said rod.

References Cited 45 LOUIS R. PRINCE, Primary Examiner,

I. W. ROSKOS, .Assistant Examiner.

U.S. C1. X.R. 138-89; 206-46 UNITED STATES PATENT OFFICE CERTIFICATE 'OFCORRECTION Patent No. 3,541,858 November 24,

Joseph E. Bonczek It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected asshown below:

Column l line 36 "its is" should read it is l 2 line 65 "gaskeets"should read gaskets Column 4 li] inthe lowermost sealing member in FIGSshould read in th uppermost sealing member 45 for proline 39 "position"s] read positions line 70 "if" should read of Colul lines 2S to 46, theClaim should read as follows l. In combination,

a Utube with at least one open end with a bore therein;

a removable internal piston-type seal telescoped into said open end andbore to seal said bore, comprising a rod adapted to telescope into saidbore sealing means on said rod telescopable with said rod into saidbore, and

seal control means on said rod for moving said sealing means intosealing position for sealing said bore or into a removable position forremoval from said bore;

a block having two parallel holes telescoped over the distal ends of theU-tube to cover said sealed open end and to support said distal endsagainst distortion;

resilient means operatively connected to said block and seal for urgingthe sealing means of said seal against liquid sealed in said tube bysaid sealing means and means for holding said block on the U-tube.

2 The Combination, as set forth in claim l with Signed and sealed this16th day of March 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, Attesting OfficerCommissioner of Pate

